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Case Study: Liqui-Mover® Pump Succeeds Where Electric Condensate Pumps Failed


liquimover SMA Fortune 100 company heats its multi-building campus from a central boiler house. To pump the return condensate, it was using electric pumps located in a sub-basement that flooded once or twice a year with up to eight feet of water. The subsequent pump failures caused heat outages throughout the campus. The customer needed a solution that would never fail, even when submerged.

The system requires up to 180,000 pph of low connectivity condensate to be returned to the boiler room in a small, six-inch return line. Also, any pumping solution needed to fit in a small sub-basement, with access through a five by five foot opening,16 feet above the floor. 


Kadant Johnson engineers worked with the customer, their engineering firm, and their boiler management company to design a Liqui-Mover condensate system that could be installed and operated in a small, flooded pit. The solution was a forced-alternating, Float Free™ pump with electronic controls above the flood level. It uses readily available air pressure to pump the condensate and a guided wave radar detects condensate levels, eliminating the issues associated with probe sensors and low connectivity condensate. The forced-alternating system uses valves to fill one pump with low-pressure condensate, while air pressure pumps condensate out of the other tank at a higher pressure. They then alternate filling and pumping. This system has few moving parts and maximizes the flow of the six-inch return line by creating continuous flow. For uninterrupted maintenance, a third pump was also included that can be activated remotely.


Kadant Johnson fast-tracked the project to coincide with existing work at the facility. The modular system was engineered and pre-assembled in sections that were lowered through the five by five-foot opening. The Liqui-Mover pump was installed over a two week period with Kadant Johnson experts onsite to assist. Whether the sub-basement is dry or flooded, the Kadant Johnson Liqui-Mover pump will operate continuously for decades.

  • Written by:

    Erich Bernhardt

    Senior Applications Engineer, Kadant Johnson

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